| Transfers from (to) other retirement benefit plans | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| The increase (decrease) in net assets available for benefits resulting from transfers from (to) other retirement benefit plans. [Refer: Assets (liabilities) of benefit plan] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Transferencias de (a) otros planes de beneficios por retiro | es | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |